The field of this invention is control valves for controlling fluid in a flowline, particularly of the type having internal bypass features.
Control valves for controlling fluid flow in a flowline have long been and are well known in the art such as disclosed in U.S. Pat. Nos. 189,916; 661,175; 1,860,510; 3,330,296; 3,347,260; 3,698,418; 3,780,758; French Pat. No. 1.912.779 and Norwegian Pat. No. 184,703, all disclosing valve elements that are rotatable to regulate fluid flow. Some valves in the prior art may be disassembled for inspection and repair without being removed from the flowline such as disclosed in U.S. Pat. No. 3,840,042. Additionally, the prior art discloses the use of multiple rotatable elements within fluid control valves to permit replacement of the valving element without removing the valve housing from the flowline, such as disclosed in U.S. Pat. Nos. 1,841,050; 2,769,456; 2,997,057; 3,700,003; and, 3,881,517. However, none disclose continued fluid operation through the valve to continue operation of the fluid flowline while such a valving element is being replaced.